In semiconductor substrate processing or medical applications, it is necessary to provide blended processing fluids of acids, alkalies, and organic solvents, which may include, e.g., mixtures of hydrogen peroxide with sulfuric acid, ammonium hydroxide, or water, or mixtures of hydrofluoric acid blended with water, acidic acid, nitric acid, or phosphoric acid. A pump is used to direct desired amounts of fluid to a processing chamber in which semiconductor wafers, photomasks, other products are being treated or processed.
The pump must be able to withstand the hostile environment created by the aggressive processing fluids. Further, contaminants in the processing fluid need to be kept to a minimum to achieve the clean environment required in high purity applications. Moreover, it is also critical that bacterial growth be inhibited.
Finally, because of the precision required of the mixed fluids, the pump must be able to deliver unusually accurate amounts of processing fluid to the processing chamber. The fluid must also be dispensed with accurate repetition.
Conventional mechanical methods of controlling the pumping action have problems dealing with these precision semiconductor applications. The accuracy needs to be improved, the cleanliness needs to be improved, and the number of particles generated can be reduced. Although electronics can be used, accuracies can still be limited by the inherent imperfection of the mechanical structure. Moreover, there still remains a concern of contamination and pump reliability because of the hostile pump environment.
There is a need, therefore, for a pump that can dispense accurate amounts of fluid with accurate repetition and provide a clean environment for the processing of the fluid therethrough.